diff --git a/README.md b/README.md
index d2d500e..14ee958 100644
--- a/README.md
+++ b/README.md
@@ -79,41 +79,42 @@ The below examples are implemented as integration tests, they should be very eas
 Otherwise, pull requests are appreciated.
 Some examples interact (via HTTPS) with a 3rd Party Blockchain Provider (3PBP).
 
-- [Generate a random address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L12)
-- [Generate an address from a SHA256 hash](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L19)
-- [Import an address via WIF](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L29)
-- [Generate a 2-of-3 P2SH multisig address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L36)
-- [Generate a SegWit address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L50)
-- [Generate a SegWit P2SH address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L60)
-- [Generate a SegWit 3-of-4 multisig address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L71)
-- [Generate a SegWit 2-of-2 P2SH multisig address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L86)
-- [Support the retrieval of transactions for an address (3rd party blockchain)](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L100)
-- [Generate a Testnet address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L121)
-- [Generate a Litecoin address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L131)
-- [Create a 1-to-1 Transaction](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L14)
-- [Create a 2-to-2 Transaction](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L28)
-- [Create (and broadcast via 3PBP) a typical Transaction](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L46)
-- [Create (and broadcast via 3PBP) a Transaction with an OP\_RETURN output](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L88)
-- [Create (and broadcast via 3PBP) a Transaction with a 2-of-4 P2SH(multisig) input](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L115)
-- [Create (and broadcast via 3PBP) a Transaction with a SegWit P2SH(P2WPKH) input](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L151)
-- [Create (and broadcast via 3PBP) a Transaction with a SegWit 3-of-4 P2SH(P2WSH(multisig)) input](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L183)
-- [Import a BIP32 testnet xpriv and export to WIF](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L8)
-- [Export a BIP32 xpriv, then import it](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L15)
-- [Export a BIP32 xpub](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L26)
-- [Create a BIP32, bitcoin, account 0, external address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L35)
-- [Create a BIP44, bitcoin, account 0, external address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L50)
-- [Create a BIP49, bitcoin testnet, account 0, external address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L66)
-- [Use BIP39 to generate BIP32 addresses](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L83)
-- [Create (and broadcast via 3PBP) a Transaction where Alice can redeem the output after the expiry](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/cltv.js#L37)
-- [Create (and broadcast via 3PBP) a Transaction where Alice and Bob can redeem the output at any time](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/cltv.js#L71)
-- [Create (but fail to broadcast via 3PBP) a Transaction where Alice attempts to redeem before the expiry](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/cltv.js#L104)
+- [Generate a random address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L30)
+- [Generate an address from a SHA256 hash](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L37)
+- [Import an address via WIF](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L48)
+- [Generate a 2-of-3 P2SH multisig address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L55)
+- [Generate a SegWit address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L69)
+- [Generate a SegWit P2SH address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L78)
+- [Generate a SegWit 3-of-4 multisig address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L88)
+- [Generate a SegWit 2-of-2 P2SH multisig address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L103)
+- [Support the retrieval of transactions for an address (3rd party blockchain)](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L117)
+- [Generate a Testnet address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L136)
+- [Generate a Litecoin address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/addresses.js#L146)
+- [Create a 1-to-1 Transaction](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L21)
+- [Create a 2-to-2 Transaction](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L36)
+- [Create (and broadcast via 3PBP) a typical Transaction](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L55)
+- [Create (and broadcast via 3PBP) a Transaction with an OP\_RETURN output](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L87)
+- [Create (and broadcast via 3PBP) a Transaction with a 2-of-4 P2SH(multisig) input](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L109)
+- [Create (and broadcast via 3PBP) a Transaction with a SegWit P2SH(P2WPKH) input](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L149)
+- [Create (and broadcast via 3PBP) a Transaction with a SegWit 3-of-4 P2SH(P2WSH(multisig)) input](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/transactions.js#L184)
+- [Import a BIP32 testnet xpriv and export to WIF](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L17)
+- [Export a BIP32 xpriv, then import it](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L24)
+- [Export a BIP32 xpub](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L35)
+- [Create a BIP32, bitcoin, account 0, external address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L44)
+- [Create a BIP44, bitcoin, account 0, external address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L59)
+- [Create a BIP49, bitcoin testnet, account 0, external address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L75)
+- [Use BIP39 to generate BIP32 addresses](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/bip32.js#L92)
+- [Create (and broadcast via 3PBP) a Transaction where Alice can redeem the output after the expiry (in the past)](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/cltv.js#L42)
+- [Create (and broadcast via 3PBP) a Transaction where Alice can redeem the output after the expiry (in the future)](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/cltv.js#L83)
+- [Create (and broadcast via 3PBP) a Transaction where Alice and Bob can redeem the output at any time](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/cltv.js#L135)
+- [Create (but fail to broadcast via 3PBP) a Transaction where Alice attempts to redeem before the expiry](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/cltv.js#L177)
 - [Recover a private key from duplicate R values](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/crypto.js#L14)
-- [Recover a BIP32 parent private key from the parent public key, and a derived, non-hardened child private key](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/crypto.js#L115)
-- [Generate a single-key stealth address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/stealth.js#L70:)
-- [Generate a single-key stealth address (randomly)](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/stealth.js#L89:)
-- [Recover parent recipient.d, if a derived private key is leaked (and nonce was revealed)](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/stealth.js#L105)
-- [Generate a dual-key stealth address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/stealth.js#L122)
-- [Generate a dual-key stealth address (randomly)](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/stealth.js#L145)
+- [Recover a BIP32 parent private key from the parent public key, and a derived, non-hardened child private key](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/crypto.js#L73)
+- [Generate a single-key stealth address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/stealth.js#L75)
+- [Generate a single-key stealth address (randomly)](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/stealth.js#L94)
+- [Recover parent recipient.d, if a derived private key is leaked (and nonce was revealed)](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/stealth.js#L110)
+- [Generate a dual-key stealth address](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/stealth.js#L127)
+- [Generate a dual-key stealth address (randomly)](https://github.com/bitcoinjs/bitcoinjs-lib/blob/master/test/integration/stealth.js#L150)
 
 If you have a use case that you feel could be listed here, please [ask for it](https://github.com/bitcoinjs/bitcoinjs-lib/issues/new)!
 
diff --git a/package.json b/package.json
index cf3db97..7f1ef7b 100644
--- a/package.json
+++ b/package.json
@@ -47,10 +47,10 @@
     "wif": "^2.0.1"
   },
   "devDependencies": {
-    "bigi": "^1.4.2",
     "bip39": "^2.3.0",
     "bip65": "^1.0.1",
     "bip68": "^1.0.3",
+    "bn.js": "4.11.8",
     "bs58": "^4.0.0",
     "dhttp": "^2.5.0",
     "hoodwink": "^1.0.0",
diff --git a/test/integration/crypto.js b/test/integration/crypto.js
index 58ae431..c46cf6b 100644
--- a/test/integration/crypto.js
+++ b/test/integration/crypto.js
@@ -1,7 +1,7 @@
 /* global describe, it */
 
 var assert = require('assert')
-var bigi = require('bigi')
+var BN = require('bn.js')
 var bitcoin = require('../../')
 var bip32 = require('bip32')
 var crypto = require('crypto')
@@ -31,11 +31,11 @@ describe('bitcoinjs-lib (crypto)', function () {
 
       // store the required information
       input.signature = scriptSignature.signature
-      input.z = bigi.fromBuffer(m)
+      input.z = new BN(m)
     })
 
-    // finally, run the tasks, then on to the math
-    var n = secp256k1.n
+    // finally, run the tasks, then on to the mathmod
+    var n = new BN(secp256k1.n.toString())
 
     for (var i = 0; i < tx.ins.length; ++i) {
       for (var j = i + 1; j < tx.ins.length; ++j) {
@@ -47,22 +47,22 @@ describe('bitcoinjs-lib (crypto)', function () {
         let rB = inputB.signature.slice(0, 32)
         assert.strictEqual(r.toString('hex'), rB.toString('hex'))
 
-        var rInv = bigi.fromBuffer(r).modInverse(n)
+        var rInv = new BN(r).invm(n)
 
-        var s1 = bigi.fromBuffer(inputA.signature.slice(32, 64))
-        var s2 = bigi.fromBuffer(inputB.signature.slice(32, 64))
+        var s1 = new BN(inputA.signature.slice(32, 64))
+        var s2 = new BN(inputB.signature.slice(32, 64))
         var z1 = inputA.z
         var z2 = inputB.z
 
-        var zz = z1.subtract(z2).mod(n)
-        var ss = s1.subtract(s2).mod(n)
+        var zz = z1.sub(z2).mod(n)
+        var ss = s1.sub(s2).mod(n)
 
         // k = (z1 - z2) / (s1 - s2)
         // d1 = (s1 * k - z1) / r
         // d2 = (s2 * k - z2) / r
-        var k = zz.multiply(ss.modInverse(n)).mod(n)
-        var d1 = ((s1.multiply(k).mod(n)).subtract(z1).mod(n)).multiply(rInv).mod(n)
-        var d2 = ((s2.multiply(k).mod(n)).subtract(z2).mod(n)).multiply(rInv).mod(n)
+        var k = zz.mul(ss.invm(n)).mod(n)
+        var d1 = ((s1.mul(k).mod(n)).sub(z1).mod(n)).mul(rInv).mod(n)
+        var d2 = ((s2.mul(k).mod(n)).sub(z2).mod(n)).mul(rInv).mod(n)
 
         // enforce matching private keys
         assert.strictEqual(d1.toString(), d2.toString())